Liquid propellant rocket



Dec. 19, 1961 P. T. BARNES LIQUID PROPELLANT ROCKET Filed June 13, 1960 FIG.

INVENTOR. PAUL T. BARNES @M ATTORN United 3,013,389 Patented Dec. 19, 1961 The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to improvements in rupturable tank closure and injector apparatus for liquid propellant rocket motors..

In co-pending application S. N. 398,904 by Richard R. Helus and Gail M. Dyer, liled December 17, 1953, now Patent No. 2,954,670, there is disclosed an organization comprising a pair of annular propellant storage tanks, each having a rupturable end closure adjacent an injector assembly which carries cutting means extending towards the end closures. Upon actuation of the rocket motor the end closures are forced into contact with the cutting means producing propellant escape openings in each end closure. The injector assembly is so constructed to provide channels to communicate the opening in each end closure with a corresponding set of injector nozzle apertures. This construction is somewhat unsatisfactory because of the amount of space taken up between the end closure of the tank and the combustion chamber, serving no useful purpose other than 'to communicate the propellants. Also the body of the ejector is somewhat expensive to fabricate, being a complex casting with several machined bearing surfaces.

One of the objects of the present invention is to provide an improved rupturable tank closure and injector apparatus which is more compact than prior art apparatus.

Another object is to provide a novel injector sub-assembly which is simple and inexpensive to fabricate.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becornes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

FIG. l is a fragmentary central section of a rocket motor showing an embodiment of the improved tank ciosure and injector apparatus of the present invention taken along line 1 1, FIG. 2; and Y FIG. 2 is a section taken along line 2-2, FIG. l.

Referring to the drawing, a conventional rocket motor tube 10, having a longitudinal axis A, forms a combustion chamber 11 at its rear end, Disposed forwardly of the combustion chamber is apparatus for storing and pressurizing liquid propellants comprising a central chamber 12 containing a solid propellant grain 14, and inner and outer annular tanks 16 and 18, of which only the rear ends are shown. Disposed at the front end of the tanks is an organization of the general type shown at the front end of the corresponding chamber and tanks disclosed in the aforementioned co-pending application whereby gases generated by tubular propellant 14 are adapted to pressurize the tanks, the speciiic embodiment of such organization, per se, not being of importance to the present invention. Wall 20 about chamber 12 and wall 22 between the tanks are stationary relative to motor tube 10 and the tanks are closed at their rear ends by an arrangement comprising a deformable annular diaphragm 24 of suitable metal and suitably fastened as by brazing at its inner and outer edges to wall 20 and motor tube 10. Diaphragm 24 is flexibly connected to wall 22 by a pair of extendiole bellows 26a, 26b, of suitable metal at an annular mid-portion 24m of the diaphragm. The annular inner and outer portions 24a and 24b of the diaphragm constitute the end closures for tanks 16 and 18.

Disposed between the inner surface of motor tube 10, and wall 20, which extends rearward from diaphragm 24, is an annular injector plate 28 having an inlet face 30 spaced from diaphragm 24 and an outlet face 32 disposed in combustion chamber 11. Injector plate 28 is provided with a series of nozzle apertures 34, 34, having their inlet orifices 36a, 3617, FIG. 2, etc., disposed in angular spaced relationship along the periphery of a reference circle B-B concentric with the tanks. A serpentine or corrugated band 38 is tixed to inlet face 30, with its corrugation folds so arranged, as best shown in PIG. 2, to form an axial partition which winds around theA inlet oriiices dividing inlet face 30 into an inner zone 30a into which one set of alternate orifices 36a, 36a open, and an outer Zone 3017, into which the other set of alternate apertures 3617, 36b open in such manner that any orifice of each set is disposed between a pair of orifices of the other set. An annular member 40 is secured to the rear edge of band 38 providing a support member and preventing axial flow about the rear edge of band 38. j

There is secured to the rear face of annular mid-pon tion 24m an annular support member 42. A suitable collapsible bellows 44 or other collapsible sealing means extends between member 40 and member 42. Apair of cylindrical cutters 46a, 46h, with their cutting edges disposed toward diaphragm inner portion 24a and diaphragm outer portion 24b are mounted to annular member 40, or otherwise suitably aftlxed to the injector as sembly. lt will be apparent that pressurization of the propellants in tanks 16 and 18 will cause diaphragm 24 to deform rearwardly forcing the diaphragm inner and outer portions 24a, 24b into contact with cutters 46a,

46b, thereby producing propellant escape openings in same. Bellows 44, annular member 40 and serpentine band 38 form inner and outer channels or compartments 48 and 50 between the opening in diaphragm inner portion 24a and set of oriiices 36a, and the opening in diacircle B-B alternately consisting of propellant from tank 16 and propellant from tank 18. An annular deflector member 52 having a concave surface 54, is disposed adjacent injector plate outlet face 32 with surface 54 opposite the outlet oriiices. Surface 54 is adapted to change the direction of the streams so that they are all directed toward a common point 56 at the apex of an imaginary cone 58 disposed within combustion chamber 11.

Preferably, there is provided an arrangement to prevent unauthorized movement of diaphragm 2.4 into contact with cutters 46a, 461: against undesired inertial force which may be applied to the diaphragm, as for example by inertial force of the propellants against the diaphragm if the rocker motor is subjected to severe acceleration or `deceleration forces, as in accidental dropping. Such arrangement comprises a brittle rupture disk 60, suitably supported in position adjacent injector plate outlet face 32 and extending across the central opening of annular plate 28, and with suitable gasket 62 between the injector plate and disk to provide a seal at the rear end of central chamber 11. Three apertures 64, spaced apart and each in registry with a corresponding injector nozzle aperture, are provided in annular member 40. Abutment pins 66, each with one end fixed to support member 42, slideably extend into each aperture 64.

Spacer pins 68 extending through the corresponding nozzle aperture, are disposed between each abutment pin and disk 60. Disk 60, spacer pins 68 and abutment pins 66 comprise a train of abutting elements adapted to maintain diaphragm 24 and cutters 46a, 4Gb in spaced relationship. The gases generated upon ignition of propellant grain 14 cause the disintegration of blow out disk 60 so that spacer pins 68 are no longer supported by disk 60 and are free to move rearward, thereby disengaging the train of abutting elements and permitting movement of diaphragm 24 against the cutters. Spacer pins 68 are preferably deformable in such manner as to permit deliection into combustion chamber 11 upon striking surface 54 to thereby free the corresponding nozzle aperture, one form of such structure being an articulated pin comprising several short segments, as shown in dashed lines.

It will 'be apparent that in contradistinction to the prior art apparatus, the present invention is relatively compact and the injector assembly is simple and inexpensive to fabricate. The amount of void space between the tank closures and the injector nozzles is practically a minimum, channels 4S, 50, being no longer than necessary to prevent obstruction of the flow by the portions of diaphragm 24 remaining attached to walls 20 and 22 after cutters 46a, 46b have opened same. Serpentine band 38 may be roll formed from strip stock, and the sub-assembly comprising plate 2S, band 38 and annular member 40 may be assembled by brazing, so that it is inexpensive and well suited for mass production.

Obviously many modifications and variations of the present invention are posible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. In a liquid propellant rocket motor, apparatus for storing and pressurizng liquid propellants comprising a central chamber containing a solid propellant grain and inner and outer concentric annular propellant storage tanks thereabout, said tanks at their rear end each having a rupturable end closure adapted to move rearwardly, said propellant grain adapted to generate gases for forcing each end closure into `contact with cutting means to produce propellant escape openings in same and for pressurizing the liquid propellants to force same out through said openings, an injector plate having an inlet face spaced from said end closures and provided with a series of nozzle apertures with their inlet orifices disposed in angularly spaced relationship along the periphery of a reference circle concentric with said tanks, the improvements, in combination, said end closures forming an annular surface between the inner tank end closure opening and the outer tank end closure opening, a serpentine band adjacent said inlet face and winding about said inlet orifices in such manner to divide said inlet face into an inner zone into which one set of angularly alternating orifices open and an outer zone into which the other set of angularly alternating orifices open, an annular member adjacent the front edge of said band, and collapsible sealing means extending -between said annular member and said annular surface formed by the end closures.

2. Apparatus in accordance with claim l including means for preventing unauthorized opening of said end closures prior to ignition of said propellant grain comprising a central opening in said injector plate through which gases produced by said solid propellant are exhausted, a brittle blowout disk disposed adjacent the outlet face of said injector plate and across said central opening, said annular member being provided with at least three angularly spaced apertures each in registry with a nozzle aperture, a like number of abutment pins each aflixed by one end to said annular surface and in registry with an aperture of the annular member, a like number of spacer pins each disposed between an abutment pin and said blowout disk and adapted to maintain said end closures and said cutting means in spaced relationship, said blowout disk adapted to disintegrate upon ignition of said solid propellant permitting said spacer pins to move rearwardly and thereby permit movement of said end closures into contact with said cutting means.

Goddard Aug. 8, 1950 Helus et al Oct. 4, 1960 

